don't get ourselves banned by repeatedly polling an expired download

static/js/download.js

@@ -6,7 +6,14 @@ document.addEventListener("DOMContentLoaded", () => {
 
     updateInterval = setInterval(() => {
         fetch(`info?code=${CODE}`)
-            .then((res) => res.json())
+            .then((res) => {
+                if (res.status === 404) {
+                    clearInterval(updateInterval);
+                    return Promise.reject("Download not found");
+                } else {
+                    return res.json();
+                }
+            })
             .then((info) => {
                 for (const [index, offset] of info.offsets.entries()) {
                     table.children[index].className = (offset > info.available) ? "unavailable" : "";
@@ -14,6 +21,7 @@ document.addEventListener("DOMContentLoaded", () => {
                 if (info.available === info.file.size) {
                     clearInterval(updateInterval);
                 }
-            });
+            })
+            .catch(console.error);
     }, 5000);
 });